The present invention relates generally to a method of, and apparatus for, driving tunnels, galleries, trenches and the like excavations.
In order to drive a tunnel it is known to use the so-called "knife-shield" apparatus such as is described in German Utility Patent No. 1 910 987. The apparatus has a frame bearing plank-shaped knives mounted adjacent to one another on the top of the frame. Each knife is associated with a double-acting hydraulic piston and cylinder unit disposed between the frame and the knife in question, so that each knife can penetrate into the ground material in a forward direction. As each knife advances, the frame is secured in position by the frictional resistance between the other knives and the surrounding material. When all the knives have been advanced, the simultaneous application of pressure fluid to all the hydraulic units in a reverse sense causes the frame to be moved forward. When apparatus of this type is used for driving a tunnel, a concreting operation, performed to fabricate a permanent tunnel lining, usually takes place immediately to the rear of the frame. This presents a serious draw-back, because in the same area of the tunnel in which concreting is to be performed, the material extracted has to be removed.
Hence, to avoid hinderance, these operations are usually performed in separate cycles, which is excessively time consuming.
Apparatus is also known which produces tunnels or galleries by utilizing metal tubes of limited thickness to form a temporary support lining for the tunnel. In this form of apparatus, the actual excavation or driving has to be effected by means of manually operated tools or knives, as a knife shield of the aforementioned type which requires an adequate support means cannot be used.
A general object of the present invention is to provide an improved method and apparatus for driving tunnels or the like.